Sorry Mojo, can't be of much help and I doubt you will find anyone using on-walls in a 2 channel setup. On-walls, in my opinion, are already a bit of a compromise (usually for aesthetics and space constraints) and the inability to effectively toe/angle them limits their effectiveness to tweak ever so slightly.
In my case, my on-walls (2xM22's and a VP180) are also supported by 4 ceiling speakers, 2 QS-4 surrounds and a pair of M3 bookshelf's as rears. Needless to say, with DTS:X or Dolby:ATMOS processing, I have no issues with holographic imaging
Now if Axiom could only figure out how to do in-floor speakers to get that truly 360-sphere sound I've been craving...
